Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, when serving files through Active Storage's proxy delivery mode, the proxy controller loads the entire requested byte range into memory before sending it. A request with a large or unbounded Range header (e.g. `bytes=0-`) could cause the server to allocate memory proportional to the file size, possibly resulting in a DoS vulnerability through memory exhaustion. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, `DirectUploadsController` accepts arbitrary metadata from the client and persists it on the blob. Because internal flags like `identified` and `analyzed` are stored in the same metadata hash, a direct-upload client can set these flags to skip MIME detection and analysis. This allows an attacker to upload arbitrary content while claiming a safe `content_type`, bypassing any validations that rely on Active Storage's automatic content type identification. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, Active Storage's `DiskService#path_for` does not validate that the resolved filesystem path remains within the storage root directory. If a blob key containing path traversal sequences (e.g. `../`) is used, it could allow reading, writing, or deleting arbitrary files on the server. Blob keys are expected to be trusted strings, but some applications could be passing user input as keys and would be affected. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.

Active Storage allows users to attach cloud and local files in Rails applications. Prior to versions 8.1.2.1, 8.0.4.1, and 7.2.3.1, Active Storage's `DiskService#delete_prefixed` passes blob keys directly to `Dir.glob` without escaping glob metacharacters. If a blob key contains attacker-controlled input or custom-generated keys with glob metacharacters, it may be possible to delete unintended files from the storage directory. Versions 8.1.2.1, 8.0.4.1, and 7.2.3.1 contain a patch.